I have a type A Oberndorf Mauser and the original caliber is marked 7x57N. Sometime after the original marking the N was stamped over with an S. What does this mean?

Jeff

N/

Thanks Alf,

I suspected it may have something to do with how the gun was regulated but thought it was a bullet weight issue. I am going to try some S&B 173's and Norma 150's to see what happens.

You may want to slug the barrel to be sure of the bore diameter. I always thought the "S" designation also meant a bullet diameter of .322 instead of the previous 8mm diameter of .318 (known as I or J).

quote:

Originally posted by Wink:
You may want to slug the barrel to be sure of the bore diameter. I always thought the "S" designation also meant a bullet diameter of .322 instead of the previous 8mm diameter of .318 (known as I or J).

Wink,

If that 7x57 of his has either a .318" or .323" bore, I doubt it will shoot well.

Mike,
I am slow. I had to read what you posted twice to catch what you were saying.
Butch

quote:

Originally posted by butchlambert:
Mike,
I am slow. I had to read what you posted twice to catch what you were saying.
Butch

But not as slow as I was. 7 or 8mm, its almost the same thing, right?

And I thought WE had a problem with the metric system, lol.

The metric system is incredibly complicated. For instance, a 7 mm rifle really has a 7.2136 mm bore, an 8 mm really has a 8.2042 mm bore and your classic .30 caliber is really a 7.8232 mm, not a 7.62 as you usually see in the literature. So there.

Damn, I thought I was gonna get to slug something.

quote:

Originally posted by jawheeler:
Damn, I thought I was gonna get to slug something.

Just don't slug your bartender. But seriously, once you get the feel for the elegant relationships contained in the metric system it's hard not to find it superior to any other measurement system. For instance:

water freezes at 0 C and boils at 100 C.
one cubic centimeter of water also equals one centiliter of water.
1 liter of water weighs 1 kilogram.
What is 1 calorie? The amount of energy it takes to raise 1 cl of water one degree.

All this makes calculations incredibly simple. If you look at a 55 gallon drum of water and somebody asks you how much it weighs in pounds, you pull out the calculator. If someone asks you how much it weighs in kg it's easy, the volume is 200 liters so it's 200 kilos, plus the weight of the drum of course.

quote:

Originally posted by Wink:
The metric system is incredibly complicated. For instance, a 7 mm rifle really has a 7.2136 mm bore, an 8 mm really has a 8.2042 mm bore and your classic .30 caliber is really a 7.8232 mm, not a 7.62 as you usually see in the literature. So there.

You are also confusing the bore diameter with the groove diameter. Bore diameter is before the rifling, i.e. the top of the land to the top of the land, the groove diameter is from the bottom of the rifling to the bottom of the rifling. 30-06 has a .300 bore and a .308 groove diameter. The .300 bore is the 7.62mm, which is the way most European calibers are measured, by bore, not groove, diameter. That's why Rigby renamed the 7x57 Mauser round to 275 Rigby, they used the bore diameter. Americans tend to use the groove diameter, because that's what jacketed bullets typically measure. But the marketing guys can hang just about any number on a cartridge, even if it has nothing to do with any dimension associated with the cartridge.